King British Holiday Food Block is a slow release complete food which lasts for up to 14 days. It is suitable for use with all tropical and coldwater fish.Weekend feeders are small starfish-shaped blocks made from a calcium matrix that slowly dissolve to release fish food into the water. King British Weekend Feeders are suitable for all coldwater & tropical fish. Each block lasts up to four days, making them ideal to feed your fish if you are away for a long weekend. Suitable for 12 small tropical fish or 5 medium size goldfish. Each pack contains four feeders.